docs: def clean_email(self):
          """ Validate that the e-mail address is unique. """
          if get_user_model().objects.filter(email__iexact=self.cleaned_data['email']):
              if userena_settings.USERENA_ACTIVATION_REQUIRED and UserenaSignup.objects.filter(user__email__iexact=self.cleaned_data['email']).exclude(activation_key=userena_settings.USERENA_ACTIVATED):
                  raise forms.ValidationError(_('This email is already in use but not confirmed. Please check your email for verification steps.'))
              raise forms.ValidationError(_('This email is already in use. Please supply a different email.'))
          return self.cleaned_data['email']